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Abstract  

The compounds [(LR2Sn)2O] {R=CH3 (Me), n-C4H9(Bn); L=C6H5CH(OH)COO}were studied by thermogravimetric and differential scanning calorimetry in a dynamic atmosphere of helium. The thermal decomposition mechanisms are similar for both compounds and occur in two consecutive steps. The TG curves of the complexes suggest the liberation of the ligand L in the first step, with probable formation of a tin oxide R2SnO intermediate. At the end of the second step free tin is obtained in accordance with the stoichiometry of the related compounds. An inverse relation betweenΔH fusion and solubility of the compounds suggests a polymeric structure for the compound with Bn ligand in relation to the compound with M ligand.

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Summary  

Seventy nine samples, including soil and rock, were collected from the agrestic region of the State of Pernambuco, Brazil. The activity concentrations of 238U and 226Ra in the samples were determined by gamma-spectrometry using an HPGe detector. The concentrations of 238U were 22 Bq . kg-1 to 22 kBq . kg-1. The concentrations of 226Ra were 14 Bq . kg-1   to 17 kBq . kg-1. The 238U/226Ra ratios in the soil were 0.7 to 3.4 (arithmetic mean 1.7). The radiometric data were evaluated to explain 238U and 226Ra migration in the soil and the possible consequences to the environment.

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Journal of Thermal Analysis and Calorimetry
Authors: V. A. Cardoso, L. M. Nunes, J. C. O. Santos, I. M. G. Santos, M. M. Conceiçăo, J. R. Santos Jr., and A. G. Souza
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